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------------------------------------------------------------------------------
-- --
-- GNAT RUNTIME COMPONENTS --
-- --
-- G N A T . T A B L E --
-- --
-- B o d y --
-- --
-- Copyright (C) 1998-2004 Ada Core Technologies, Inc. --
-- --
-- GNAT is free software; you can redistribute it and/or modify it under --
-- terms of the GNU General Public License as published by the Free Soft- --
-- ware Foundation; either version 2, or (at your option) any later ver- --
-- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
-- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
-- for more details. You should have received a copy of the GNU General --
-- Public License distributed with GNAT; see file COPYING. If not, write --
-- to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, --
-- MA 02111-1307, USA. --
-- --
-- As a special exception, if other files instantiate generics from this --
-- unit, or you link this unit with other files to produce an executable, --
-- this unit does not by itself cause the resulting executable to be --
-- covered by the GNU General Public License. This exception does not --
-- however invalidate any other reasons why the executable file might be --
-- covered by the GNU Public License. --
-- --
-- GNAT was originally developed by the GNAT team at New York University. --
-- Extensive contributions were provided by Ada Core Technologies Inc. --
-- --
------------------------------------------------------------------------------
with System; use System;
with System.Memory; use System.Memory;
with Unchecked_Conversion;
package body GNAT.Table is
Min : constant Integer := Integer (Table_Low_Bound);
-- Subscript of the minimum entry in the currently allocated table
Max : Integer;
-- Subscript of the maximum entry in the currently allocated table
Length : Integer := 0;
-- Number of entries in currently allocated table. The value of zero
-- ensures that we initially allocate the table.
Last_Val : Integer;
-- Current value of Last.
-----------------------
-- Local Subprograms --
-----------------------
procedure Reallocate;
-- Reallocate the existing table according to the current value stored
-- in Max. Works correctly to do an initial allocation if the table
-- is currently null.
pragma Warnings (Off);
-- Turn off warnings. The following unchecked conversions are only used
-- internally in this package, and cannot never result in any instances
-- of improperly aliased pointers for the client of the package.
function To_Address is new Unchecked_Conversion (Table_Ptr, Address);
function To_Pointer is new Unchecked_Conversion (Address, Table_Ptr);
pragma Warnings (On);
--------------
-- Allocate --
--------------
function Allocate (Num : Integer := 1) return Table_Index_Type is
Old_Last : constant Integer := Last_Val;
begin
Last_Val := Last_Val + Num;
if Last_Val > Max then
Reallocate;
end if;
return Table_Index_Type (Old_Last + 1);
end Allocate;
------------
-- Append --
------------
procedure Append (New_Val : Table_Component_Type) is
begin
Increment_Last;
Table (Table_Index_Type (Last_Val)) := New_Val;
end Append;
--------------------
-- Decrement_Last --
--------------------
procedure Decrement_Last is
begin
Last_Val := Last_Val - 1;
end Decrement_Last;
----------
-- Free --
----------
procedure Free is
begin
Free (To_Address (Table));
Table := null;
Length := 0;
end Free;
--------------------
-- Increment_Last --
--------------------
procedure Increment_Last is
begin
Last_Val := Last_Val + 1;
if Last_Val > Max then
Reallocate;
end if;
end Increment_Last;
----------
-- Init --
----------
procedure Init is
Old_Length : constant Integer := Length;
begin
Last_Val := Min - 1;
Max := Min + Table_Initial - 1;
Length := Max - Min + 1;
-- If table is same size as before (happens when table is never
-- expanded which is a common case), then simply reuse it. Note
-- that this also means that an explicit Init call right after
-- the implicit one in the package body is harmless.
if Old_Length = Length then
return;
-- Otherwise we can use Reallocate to get a table of the right size.
-- Note that Reallocate works fine to allocate a table of the right
-- initial size when it is first allocated.
else
Reallocate;
end if;
end Init;
----------
-- Last --
----------
function Last return Table_Index_Type is
begin
return Table_Index_Type (Last_Val);
end Last;
----------------
-- Reallocate --
----------------
procedure Reallocate is
New_Size : size_t;
begin
if Max < Last_Val then
pragma Assert (not Locked);
while Max < Last_Val loop
-- Increase length using the table increment factor, but make
-- sure that we add at least ten elements (this avoids a loop
-- for silly small increment values)
Length := Integer'Max
(Length * (100 + Table_Increment) / 100,
Length + 10);
Max := Min + Length - 1;
end loop;
end if;
New_Size :=
size_t ((Max - Min + 1) *
(Table_Type'Component_Size / Storage_Unit));
if Table = null then
Table := To_Pointer (Alloc (New_Size));
elsif New_Size > 0 then
Table :=
To_Pointer (Realloc (Ptr => To_Address (Table),
Size => New_Size));
end if;
if Length /= 0 and then Table = null then
raise Storage_Error;
end if;
end Reallocate;
-------------
-- Release --
-------------
procedure Release is
begin
Length := Last_Val - Integer (Table_Low_Bound) + 1;
Max := Last_Val;
Reallocate;
end Release;
--------------
-- Set_Item --
--------------
procedure Set_Item
(Index : Table_Index_Type;
Item : Table_Component_Type)
is
begin
if Integer (Index) > Last_Val then
Set_Last (Index);
end if;
Table (Index) := Item;
end Set_Item;
--------------
-- Set_Last --
--------------
procedure Set_Last (New_Val : Table_Index_Type) is
begin
if Integer (New_Val) < Last_Val then
Last_Val := Integer (New_Val);
else
Last_Val := Integer (New_Val);
if Last_Val > Max then
Reallocate;
end if;
end if;
end Set_Last;
begin
Init;
end GNAT.Table;
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